GCSE physics energy question help!

hi, i'm stuck with more physics questions :frown:

The fuel cells of an aeroplane provide a maximum total power of 24 kW. The aeroplane also carries a large rechargeable battery.
Show, by calculation, that the aeroplane needs this extra source of power to climb to 1000m in 3 minutes.

i managed to this part:
gravitational potential energy = mass x g x height
GPE = 600 x 10 x 1000
GPE = 6000000J

The aeroplane uses fuel cells connected together in series in a ‘stack’. The voltage of each fuel cell is 0.6V. The maximum current in each fuel cell is 30A.
Show that there must be more than 1300 fuel cells in the stack.

^ stuck with this one

thank you in advance! help appreciated :smile:

Reply 1

AnythingWorks

10

Can you send me a picture of the exact question?

Reply 2

sammy_li11

OP

10

Original post by AnythingWorks

Can you send me a picture of the exact question?

should be here now

also i realised that the part i said i did was in fact part ii and not iii

Reply 3

AnythingWorks

10

Leave it. The fuel cells provide 4320000 energy. This can be calculated by mutliplyuing power in W by time in seconds.
The power supplied by one fuel cell is V*A= 30*0.6=18.
The energy supplied by one fuel cell should be 18*3*60=3240.
Divide total energy by this value.= 4320000/3240 to get 1333.333. fuel cells. Or rounded to 1300.

Reply 4

sammy_li11

OP

10

ahh i see now, thank you so much!

Original post by AnythingWorks

Leave it. The fuel cells provide 4320000 energy. This can be calculated by mutliplyuing power in W by time in seconds.
The power supplied by one fuel cell is V*A= 30*0.6=18.
The energy supplied by one fuel cell should be 18*3*60=3240.
Divide total energy by this value.= 4320000/3240 to get 1333.333. fuel cells. Or rounded to 1300.